FIG. 7 is a perspective view illustrating a conventional two-dimensional image pick-up device disclosed in the Japanese Laid-Open Patent Publication (unexamined) No. 58-69173, FIG. 8 is an exploded perspective view illustrating an element moving carriage and guide rail of the conventional two-dimensional image pick-up device, and FIG. 9 is a sectional view illustrating that the element moving carriage and the guide rail in FIG. 8 are in an assembled state.
In these drawings, reference numeral 1 indicates a frame of the two-dimensional image pick-up device, numeral 2 indicates the guide rail mounted on the frame 1, and numeral 3 indicates the element moving carriage which is supported on the guide rail 2 through the bearings 4, 5 (see FIGS. 8 and 9) so as to be movable in the direction of the arrows A and B. The one-dimensional image pick-up element (not illustrated) is attached to the element moving carriage 3. Numeral 6 indicates an arm of the element moving carriage 3, numeral 7 indicates a spring for downward partial loading connected to the arm 6, numeral 8 indicates a micrometer head which is disposed beneath the arm 6 and securely fitted to the frame 1 through a fitting member 9. The micrometer head 8 having a spindle 10 connected to the arm 6 comprises a motion converting mechanism 11 of micrometer type which converts an inputted rotary motion to a linear motion in the axial direction of the spindle 10, and a rotary encoder 12 which detects the rotary motion and generates a pulse for each rotary motion of a specified angle, so that the spindle 10 pushes up the arm 6 of the element moving carriage 3 against the spring 7. Numeral 13 indicates an input gear mounted on the rotary input shaft of the micrometer head 8, numeral 14 indicates an electric motor installed in the vicinity of the micrometer head 8, and numeral 15 indicates an output gear engaged with the input gear 13. Numeral 16 indicates an upper side limit switch disposed above the element moving carriage 3, and numeral 17 indicates a lower side limit switch disposed beneath the element moving carriage 3. These upper and lower side limit switches 16 and 17 automatically stop the motor 14 when the element moving carriage 3 moving up and down (in linear motion) reaches a prescribed position and turns the switches on. Numeral 18 indicates an optical system which generates image of an original picture on the focal plane, and numeral 19 indicates a disc carriage for exchanging filters. A red filter 20, a green filter 21, a blue filter 22 and a black-and-white filter 23 are respectively arranged in the filter exchanging carriage 19 with equal distance therebetween. Numeral 24 indicates a filter exchanging electric motor which intermittently drives the filter exchanging carriage 19 rotationally, so that each of red, green, blue and black-and-white filers 20 to 23 is exchanged and comes at the position corresponding to the optical system 18.
A conventional device of above construction operates as follows.
When the motor 14 starting, the rotary input shaft of the motion converting mechanism 11 is rotationally driven through the output gear 15 and the input gear 13, and the rotation is converted to a linear motion by the motion converting mechanism 11 and transmitted to the micrometer head 8, whereby the arm 6 of the element moving carriage 3 starts a linear motion so that the one-dimensional image pick-up element of the element moving carriage 3 is scanned along the guide rail 2. The range of the linear motion of the element moving carriage 3 at the time of scanning is determined by counting pulses from the rotary encoder 12. Further, as the result of intermittent rotational drive of the filter exchanging carriage 19 by means of the filter exchanging motor 24, any one of the red, green, blue and black-and-white filters can alternatively assume a position in the light path behind the position of optical system 18.
Since the conventional two-dimensional image pick-up device is constructed as described above, the element moving carriage 3 and the filter exchanging carriage 19 are individually driven by the two motors 14 and 24 for their respective exclusive use. Moreover, the rotation of the motor 14 is converted to a linear motion and transmitted to the element moving carriage 3, and the micrometer head 8 is required for the subscanning of the element moving carriage 3. Accordingly, a problem exists in that the conventional device is undesirably large-sized as a whole. Besides, since the filter exchanging carriage 19 is of rotary type, the size of the color filters is required to correspond to the subscanning distance of the one-dimensional image pick-up element 25 at the time of exchanging the filters, whereby the color filters are also obliged to be large-sized. As a result the filter exchanging carriage 19 itself is also large-sized. This brings about such a drawback as increase in cost.